Revision: Tue, 23 Jun 2020 11:59:44 GMT

Application Lifecycle

Spiral Framework can work using classic Nginx/PHP-FPM setup. But the highest effectiveness can be achieved using an embedded application server (based on RoadRunner). The server creates a set of php processes for each dispatching/communication method (HTTP, GRPC, Queue, etc.).

Every PHP process will only work within a single request/task. It allows you to write code as if you would typically do in classic frameworks (share nothing approach). You can also use every library as in the past with only minor exceptions.

By keeping the application in resident memory, you can drastically increase performance and also offload part of functionality to the application server.

Read more about Framework and application server symbiosis here. Read about PSR-7 request flow here.

Application Server

You can configure the number of workers, memory limits, and other extensions using .rr.yaml file:

http:
  address: 0.0.0.0:8080
  workers:
    command: "php app.php"

jobs:
  dispatch:
    app-job-*.pipeline: "local"
  pipelines:
    local.broker: "ephemeral"
  consume: ["local"]
  workers:
    command: "php app.php"
    pool.numWorkers: 2

static:
  dir:    "public"
  forbid: [".php", ".htaccess"]

limit:
  services:
    http.maxMemory: 100
    jobs.maxMemory: 100

To set the number of workers for HTTP:

http:
  address: 0.0.0.0:8080
  workers:
    command:         "php app.php"
    pool.numWorkers: 4

Developer Mode

To force worker reload after every request (full debug mode) and limit processing to single worker:

http:
  address: 0.0.0.0:8080
  workers:
    command:         "php app.php"
    pool.numWorkers: 1
    pool.maxJobs:    1

You can read more about RoadRunner here.

Application Kernel

Every worker will contain a single application instance. Default application skeleton(s) are based on spiral/boot.

The package allows quick application instantiation via static factory method init:

$app = \App\App::init(['root' => __DIR__]);

Application Kernel initiates your application state and IoC configuration using a set of bootloaders:

class App extends Kernel
{
    /*
     * List of components and extensions to be automatically registered
     * within system container on application start.
     */
    protected const LOAD = [
        // Environment configuration
        DotEnv\DotenvBootloader::class,

        // Core Services
        Bootloader\DebugBootloader::class,
        Bootloader\SnapshotsBootloader::class,
        Bootloader\I18nBootloader::class,

        // Security and validation
        Bootloader\Security\EncrypterBootloader::class,

        // ...
    ];
}

The bootloaders will only be invoked once, without request/task context after that application will stay in the process memory permanently. Since the application bootload only happens once for many requests, you can add many components and extensions without the performance penalty (still, watch the memory consumption).

Gotchas

There are a couple of limitations to be aware of.

Memory Leaks

Since the application stays in memory for a long time, even a small memory leak might lead to the process restart. RoadRunner will monitor memory consumption and perform a soft reset, but it is best to avoid memory leaks in your application source code.

Though Framework and all of its components are written with memory management in mind, you still have to make sure that your domain code is not leaking.

Application State

Any service declared as singleton will remain in the application memory till the process end. Try to avoid storing any user data or open resources in such services.

Framework includes a set of instruments to simplify the development process and avoid memory/state leaks such as IoC Scopes, Cycle ORM, Immutable Configs, Domain Cores, Routes, and Middleware.

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